Objective: To assess the possible role of neutrophils in the pathogenesis of recurrent aphthous ulceration (RAU) by evaluating and comparing the phagocytic functions of salivary and peripheral blood neutrophils in patients with recurrent aphthous ulcers and in healthy subjects. Method and Materials: The study comprised 30 RAU and 30 healthy subjects. Neutrophils were separated from the unstimulated saliva and peripheral blood of RAU patients and healthy subjects. Then, the phagocytic activity and ingestion ability were determined using Candida as targets. Results: Salivary and peripheral blood neutrophils in RAU patients showed significant reduction (P .05) in phagocytic activity as compared to controls. The ingestion ability of salivary and blood neutrophils was reduced in RAU patients, but not significantly as compared to controls. The ingestion ability of salivary neutrophils was significantly reduced (P = .019) in comparison to blood neutrophils in RAU patients. There was no significant difference between the phagocytic activities of salivary and blood neutrophils in RAU. Conclusion: Phagocytic functions of salivary and peripheral blood neutrophils were reduced in RAU patients as compared to healthy subjects. The ingestion ability of salivary neutrophils was also decreased with that of peripheral blood neutrophils in RAU patients. All the above findings revealed that RAU is characterized by consistent changes in salivary and peripheral blood neutrophil functions, thus suggesting that the pathophysiology of RAU may be associated with reduction in phagocytic functions of neutrophils. Schlagwörter: ingestion ability, neutrophils, phagocytic activity, recurrent aphthous ulcer